diff --git a/__tests__/controllers/CartController.test.ts b/__tests__/controllers/CartController.test.ts
new file mode 100644
index 0000000..a7e39f8
--- /dev/null
+++ b/__tests__/controllers/CartController.test.ts
@@ -0,0 +1,75 @@
+import { Request, Response } from 'express';
+import { Cart, ICart, Order } from '../mongoose/Schema.test';
+import { config } from 'dotenv';
+
+config();
+
+export async function addToCart(req: Request, res: Response) {
+  try {
+    const { userId, productId } = req.body;
+    if (!productId) {
+      res.status(400).json({ error: 'Product id is required.' });
+      return;
+    }
+    let cart: ICart | null = await Cart.findOne({ userId });
+    if (!cart) {
+      cart = await Cart.create({
+        userId,
+        products: { [productId]: 1 },
+      });
+    } else {
+      const currentQuantity = cart.products[productId];
+      if (currentQuantity === undefined) {
+        cart.products[productId] = 1;
+      } else {
+        cart.products[productId] += 1;
+      }
+      cart.markModified('products');
+    }
+
+    await cart.save();
+    res.status(200).json(cart);
+  } catch (error) {
+    console.error('Error adding product to cart:', error);
+    res.status(500).json({ error: 'An error occurred while adding the product to the cart.' });
+  }
+}
+
+export async function listCart(req: Request, res: Response) {
+  try {
+    const { userId } = req.body;
+    const cart = await Cart.findOne({ userId });
+    if (!cart) {
+      res.status(404).json({ error: 'Cart not found.' });
+      return;
+    }
+    res.status(200).json(cart.products);
+  } catch (error) {
+    console.error('Error listing cart:', error);
+    res.status(500).json({ error: 'An error occurred while listing the cart.' });
+  }
+}
+
+export async function checkout(req: Request, res: Response) {
+
+  const { userId } = req.body;
+  const usersCart = await Cart.findOne({ userId });
+
+  if (!usersCart) {
+    res.status(404).json({ error: 'Cart not found.' });
+    return;
+  }
+
+  const order = await Order.create({
+    userId,
+    products: usersCart.products,
+  });
+
+  await removeCart(userId);
+  // sendEmailasync(order.id, userId);
+  res.status(200).json(order);
+}
+
+async function removeCart(userId: string) {
+  await Cart.deleteOne({ userId });
+}
\ No newline at end of file
diff --git a/__tests__/controllers/ProductController.test.ts b/__tests__/controllers/ProductController.test.ts
new file mode 100644
index 0000000..37a17f1
--- /dev/null
+++ b/__tests__/controllers/ProductController.test.ts
@@ -0,0 +1,58 @@
+import { Request, Response } from 'express';
+import { Product, IProduct } from '../mongoose/Schema';
+
+export async function createProduct(req: Request, res: Response) {
+  try {
+    const { name, description, price, userId } = req.body;
+    if(!name || !description || !price || !userId) {
+      res.status(400).json({ error: 'Name, description, price are required.' });
+      return;
+    }
+    
+    const productExists = await Product.exists({ name, userId });
+    if(productExists) {
+      res.status(400).json({ error: 'Product already exists.' });
+      return;
+    }
+    const product: IProduct = await Product.create({
+      name,
+      description,
+      price,
+      userId: userId,
+    });
+
+    res.status(201).json(product);
+  } catch (error) {
+    console.error('Error creating product:', error);
+    res.status(500).json({ error: 'An error occurred while creating the product.' });
+  }
+}
+
+export async function listProducts(req: Request, res: Response) {
+  try {
+    const { page, limit } = req.query;
+    const dbPage = Number(page) || 0;
+    const dbLimit = Number(limit) || 50;
+    const products = await Product.find().sort({ price: 1 }).skip(Number(dbPage) * Number(dbLimit)).limit(Number(dbLimit));
+
+    res.json(products);
+  } catch (error) {
+    console.error('Error listing products:', error);
+    res.status(500).json({ error: 'An error occurred while listing the products.' });
+  }
+}
+
+export async function getProduct(req: Request, res: Response) {
+  const { id } = req.params;
+  try {
+    const product = await Product.findById(id);
+    if(!product) {
+      res.status(404).json({ error: 'Product not found.' });
+      return;
+    }
+    res.json(product);
+  } catch (error) {
+    console.error('Error getting product:', error);
+    res.status(404).json({ error: 'Product not found.' });
+  }
+}
diff --git a/__tests__/controllers/UserController.test.ts b/__tests__/controllers/UserController.test.ts
new file mode 100644
index 0000000..634002b
--- /dev/null
+++ b/__tests__/controllers/UserController.test.ts
@@ -0,0 +1,87 @@
+import { Request, Response } from 'express';
+import bcrypt from 'bcryptjs';
+import jwt from 'jsonwebtoken';
+import { User, IUser } from '../mongoose/Schema';
+import { clearJwtCookie, setJwtCookie } from '../middlewares/checkAuth.test';
+import validate from 'deep-email-validator';
+
+export async function createUser(req: Request, res: Response) {
+  try {
+    const { email, password, address } = req.body;
+    const isValidEmail = await validate(email);
+    if (!isValidEmail.valid) {
+      console.error('Email is invalid:', isValidEmail.validators);
+      return res.status(400).json({ error: 'Email is invalid' });
+    }
+
+    if (!(password && address)) {
+      return res.status(400).json({ error: 'All inputs are required' });
+    }
+    // checkIfUserExists return true if the user exists
+    const userExists = await User.exists({ email });
+    if(userExists) {
+      return res.status(400).json({ error: 'User already exists, Try login :)' });
+    }
+
+    const hashedPassword = await bcrypt.hash(password, 10);
+
+    const user: IUser = await User.create({
+      email,
+      password: hashedPassword,
+      address,
+    });
+
+    res.status(200).json({
+      massage: 'User created successfully'
+    });
+  } catch (error) {
+    console.error('Error creating user:', error);
+    res.status(500).json({ error: 'An error occurred while creating the user.' });
+  }
+}
+
+export async function login(req: Request, res: Response) {
+  try {
+    const { email, password } = req.body;
+
+    // Check if the user exists
+    const user: IUser | null = await User.findOne({ email });
+    if (!user) {
+      console.error('User not found');
+      return res.status(401).json({ error: 'Invalid email or password' });
+    }
+
+    // Compare the provided password with the stored password
+    const isPasswordCorrect = await bcrypt.compare(password, user.password);
+    if (!isPasswordCorrect) {
+      console.error('Invalid password');
+      return res.status(401).json({ error: 'Invalid email or password' });
+    }
+
+    const payload = {
+      userId: user._id
+    }
+    // Generate a JWT
+    const token = jwt.sign(payload, process.env.JWT_SECRET as string, { expiresIn: '1d' });
+
+    setJwtCookie(res, token);
+
+    // Send the JWT as the response
+    res.status(200).json({
+      token
+    });
+  } catch (error) {
+    console.error('Error during login:', error);
+    res.status(500).json({ error: 'An error occurred during login' });
+  }
+}
+
+export async function logout(req: Request, res: Response) {
+  try {
+    clearJwtCookie(res);
+    res.status(200).json({ message: 'Logout successful' });
+  } catch (error) {
+    console.error('Error during logout:', error);
+    res.status(500).json({ error: 'An error occurred during logout' });
+  }
+}
\ No newline at end of file
diff --git a/__tests__/index.test.ts b/__tests__/index.test.ts
new file mode 100644
index 0000000..ec1dc24
--- /dev/null
+++ b/__tests__/index.test.ts
@@ -0,0 +1,39 @@
+import express from 'express';
+import mongoose from 'mongoose';
+import cookieParser from 'cookie-parser';
+
+import userRouter from './routes/user';
+import productRouter from './routes/product';
+import cartRouter from './routes/cart';
+
+const env = require('dotenv').config().parsed;
+
+const app = express();
+const PORT = env.PORT || 3000;
+
+app.use(express.json());
+app.use(cookieParser())
+
+// Connect to MongoDB using Mongoose
+mongoose.connect(env.DATABASE_URL);
+
+const db = mongoose.connection;
+
+// Check for DB connection
+db.on('error', () => {
+  console.error.bind(console, 'MongoDB connection error:')
+  process.exit(1);
+});
+db.once('open', () => {
+  console.log('Connected to MongoDB');
+});
+
+// Routes
+app.use('/users', userRouter);
+app.use('/products', productRouter);
+app.use('/cart', cartRouter);
+
+// Start server
+app.listen(PORT, () => { 
+  console.log(`Server started on port ${PORT}`);
+});
diff --git a/__tests__/middlewares/checkAuth.test.ts b/__tests__/middlewares/checkAuth.test.ts
new file mode 100644
index 0000000..9c62104
--- /dev/null
+++ b/__tests__/middlewares/checkAuth.test.ts
@@ -0,0 +1,33 @@
+import { Request, Response, NextFunction } from 'express';
+import jwt from 'jsonwebtoken';
+
+interface AuthenticatedRequest extends Request {
+  userId?: string;
+}
+
+// Middleware function to authenticate requests
+export function authenticateToken(req: AuthenticatedRequest, res: Response, next: NextFunction) {
+
+  const token = req.cookies.access_token;
+  if (!token) {
+    return res.status(401).json({ error: 'Unauthorized' });
+  }
+
+  jwt.verify(token, process.env.JWT_SECRET as string, (err: any, decoded: { userId: any; }) => {
+    if (err) {
+      return res.status(401).json({ error: 'In Valid Token' });
+    }
+    req.body.userId = decoded.userId;
+    next();
+  });
+}
+
+// Set JWT as cookie in the response
+export function setJwtCookie(res: Response, token: string) {
+  res.cookie('access_token', token, { httpOnly: true });
+}
+
+// Clear JWT cookie in the response
+export function clearJwtCookie(res: Response) {
+  res.clearCookie('access_token');
+}
diff --git a/__tests__/mongoose/Schema.test.ts b/__tests__/mongoose/Schema.test.ts
new file mode 100644
index 0000000..0a1157b
--- /dev/null
+++ b/__tests__/mongoose/Schema.test.ts
@@ -0,0 +1,74 @@
+import mongoose, { Schema, Document } from 'mongoose';
+
+export interface IUser extends Document {
+  email: string;
+  password: string;
+  address: string;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+export interface IProduct extends Document {
+  name: string;
+  description: string;
+  price: number;
+  userId: string;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+export interface ICart extends Document {
+  userId: string;
+  products: { [itemId: string]: number };
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+export interface IOrder extends Document {
+  userId: string;
+  products: { [itemId: string]: number };
+  emailSent: boolean;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+const UserSchema: Schema = new Schema({
+  email: { type: String, required: true, unique: true },
+  password: { type: String, required: true },
+  address: { type: String, required: true },
+  createdAt: { type: Date, default: Date.now },
+  updatedAt: { type: Date, default: Date.now },
+});
+
+const ProductSchema: Schema = new Schema({
+  name: { type: String, required: true },
+  description: { type: String, required: true },
+  price: { type: Number, required: true },
+  userId: { type: Schema.Types.ObjectId, ref: 'User', required: true },
+  createdAt: { type: Date, default: Date.now },
+  updatedAt: { type: Date, default: Date.now },
+});
+
+const CartSchema: Schema = new Schema({
+  userId: { type: Schema.Types.ObjectId, ref: 'User', required: true, unique: true },
+  products: { type: Schema.Types.Mixed, default: {} },
+  createdAt: { type: Date, default: Date.now },
+  updatedAt: { type: Date, default: Date.now },
+});
+
+const OrderSchema: Schema = new Schema({
+  userId: { type: Schema.Types.ObjectId, ref: 'User', required: true },
+  products: { type: Schema.Types.Mixed, default: {} },
+  emailSent: { type: Boolean, default: false },
+  createdAt: { type: Date, default: Date.now },
+  updatedAt: { type: Date, default: Date.now },
+});
+
+ProductSchema.index({ name: 1, userId: 1 }, { unique: true });
+
+const User = mongoose.model<IUser>('User', UserSchema);
+const Product = mongoose.model<IProduct>('Product', ProductSchema);
+const Cart = mongoose.model<ICart>('Cart', CartSchema);
+const Order = mongoose.model<IOrder>('Order', OrderSchema);
+
+export { User, Product, Cart, Order };
diff --git a/__tests__/routes/cart.test.ts b/__tests__/routes/cart.test.ts
new file mode 100644
index 0000000..10f68ef
--- /dev/null
+++ b/__tests__/routes/cart.test.ts
@@ -0,0 +1,14 @@
+import express from 'express';
+import { authenticateToken } from '../middlewares/checkAuth.test';
+import { addToCart, listCart, checkout } from '../controllers/CartController.test';
+
+
+
+const cartRouter = express.Router();
+
+cartRouter.post('/', authenticateToken, addToCart);
+cartRouter.get('/', authenticateToken, listCart);
+
+cartRouter.post('/checkout', authenticateToken, checkout);
+
+export default cartRouter;
\ No newline at end of file
diff --git a/__tests__/routes/product.test.ts b/__tests__/routes/product.test.ts
new file mode 100644
index 0000000..43d344b
--- /dev/null
+++ b/__tests__/routes/product.test.ts
@@ -0,0 +1,12 @@
+import express from 'express';
+import { authenticateToken } from '../middlewares/checkAuth.test';
+import { createProduct, listProducts, getProduct } from '../controllers/ProductController.test';
+
+const productRouter = express.Router();
+
+productRouter.post('/', authenticateToken, createProduct)
+productRouter.get('/', listProducts);
+productRouter.get('/:id', getProduct);
+
+
+export default productRouter;
\ No newline at end of file
diff --git a/__tests__/routes/user.test.ts b/__tests__/routes/user.test.ts
new file mode 100644
index 0000000..efb5204
--- /dev/null
+++ b/__tests__/routes/user.test.ts
@@ -0,0 +1,10 @@
+import express from 'express';
+import { createUser, login, logout } from '../controllers/UserController.test';
+
+const userRouter = express.Router();
+
+userRouter.post('/', createUser);
+userRouter.post('/login', login);
+userRouter.post('/logout', logout);
+
+export default userRouter;
\ No newline at end of file
diff --git a/__tests__/services/sendGrid.test.ts b/__tests__/services/sendGrid.test.ts
new file mode 100644
index 0000000..a5ae023
--- /dev/null
+++ b/__tests__/services/sendGrid.test.ts
@@ -0,0 +1,26 @@
+// import { config } from "dotenv";
+// import { User, Order } from "../mongoose/Schema";
+// import client from '@sendgrid/mail';
+// config();
+
+// export async function sendEmailasync(orderId:string, userId: string) {
+//   console.log(`Sending email for order ${orderId} to user ${userId}`);
+//   try {
+//     client.setApiKey(process.env.SENDGRID_API_KEY);
+//     const msg = {
+//       to: await User.findOne({ _id: userId }).select('email'),
+//       from: process.env.EMAIL_FROM,
+//       subject: 'Order Confirmation',
+//       text: 'Your order has been placed',
+//       html: '<strong>Thank you for shopping with us!</strong>'
+//     };
+//     await client.send(msg);
+//     console.log(`Email sent for order ${orderId} to user ${userId}`);
+//     // Update the order to indicate email has been sent
+//     await Order.findOne({ _id: orderId }).updateOne({ emailSent: true });
+//     console.log(`Updated order ${orderId} to indicate email has been sent`);
+//     return;
+//   } catch (error) {
+//     console.error('Error sending email:', error);
+//   }
+// };
\ No newline at end of file